Method for needle positioning and lead implantation for sacral neuromodulation

ABSTRACT

A method for needle positioning for lead implantation for sacral neuromodulation uses fluoroscopy to locate anatomical landmarks. Markings on the skin of the patient are made to determine optimal positioning of a foramen needle used to position the leads and electrodes of an implantable electrical stimulator.

FIELD OF THE DISCLOSURE

The disclosure relates to a method for needle positioning and leadimplantation for sacral neuromodulation.

BACKGROUND

Electrical stimulation of somatic afferent pathways in the sacral spinalroots (as well as the pudendal nerve or posterior tibial nerve) caninhibit bladder activity in both humans and animals and is clinicallyeffective in treating overactive bladder symptoms. Stimulation of thesacral S3 spinal root is currently an FDA approved therapy for the lowerurinary tract disorders including bladder overactivity, urgency,frequency, incontinence, and urinary retention. Stimulation is also anFDA approved therapy for bowel control. Although the mechanismsunderlying neuromodulation are not totally understood, this type oftherapy has become popular because bowel control and lower urinary tractdysfunctions in some patients are difficult to manage with medication.

Sacral neuromodulation requires an invasive (albeit a minimallyinvasive) procedure to implant a stimulator (e.g., InterStim®, MedtronicInc.) and electrodes, which are also referred to as the leads. While theimplantable stimulators and leads have been engineered and designed forefficiency, the success of the clinical outcome still depends heavily onthe surgical technique. It requires skilled medical staff to insert theneedle for optimal lead position relative to the nerve. Thus, currentneuromodulation treatments can be effective to suppress bladderoveractivity and bowel control, but only if the proper surgicaltechnique is observed.

Because of the expense and inconvenience of the procedure, manyindividuals that could potentially benefit from sacral neuromodulationdo not consider sacral neuromodulation in light of the variable outcomeand the potential added complications if an additional procedure isnecessary to improve the clinical outcome that the first procedurefailed to achieve. Thus, there exists a need for an improved method forneedle positioning and lead implantation for sacral neuromodulation.

SUMMARY OF THE DISCLOSURE

The disclosed method is for positioning a foramen needle to implant alead of an electrical stimulator for sacral neuromodulation of apatient. In one embodiment, the method comprises: visualizing withfluoroscopy an anterior/posterior view of the sacrum and sacroiliacjoints of the patient; marking on the skin of the patient a midline ofthe sacrum vertically and a horizontal line from one sacroiliac joint tothe other sacroiliac joint; marking a first point on the horizontal linelocated a first distance in a first lateral direction from the sacralmidline, wherein the first distance approximates a first midline of adesired sacral foramen; locating the first midline of the desired sacralforamen using the fluoroscopic anterior/posterior view and the firstpoint and marking the skin of the patient with a first midline verticalline; marking the skin of the patient at a second distance and a thirddistance from the horizontal line superiorly on the first midlinevertical line, thereby approximating where the desired foramen should belocated to place the needle; marking the skin of the patient with afirst medial vertical line representing the medial portion of the firstsacral edge using the fluoroscopic anterior/posterior view; locating thedesired sacral foramen with fluoroscopy in a lateral view; and placingthe needle through the skin at an angle using the skin markings at oneof the second and third markings, beginning medially at the firstmidline vertical line and progressing laterally to the first medialvertical line until a distal end of the needle drops into the desiredsacral foramen.

The disclosed method can also include: marking a second point on thehorizontal line located the first distance in a second lateral directionfrom the sacral midline; locating a second midline of another desiredsacral foramen using the fluoroscopic anterior/posterior view and thesecond point and marking the skin of the patient with a second midlinevertical line, the another desired sacral foramen opposite the desiredsacral foramen; marking the skin of the patient at the second distanceand the third distance from the horizontal line superiorly on the secondmidline vertical line, thereby approximating where the another desiredforamen should be located to place the needle; and marking the skin ofthe patient with a second medial vertical line representing the medialportion of the second sacral edge using the fluoroscopicanterior/posterior view.

In an embodiment, the needle angle is approximately 45 degrees. However,the needle angle is varied depending on the body habitus of the patient.The placing of the needle can be done under fluoroscopic visualization.

In an exemplary embodiment, after the distal end of the needle dropsinto the desired sacral foramen, the angle of the needle is adjusteduntil the needle is 1 cm from the inferior edge of the desired sacralforamen and parallel to the inferior edge of the desired sacral foramen.The angle of the needle can be adjusted using the fluoroscopicanterior/posterior view until the needle is parallel to the first medialvertical line.

In order to confirm placement of the needle, electricity can beconducted through the needle. In this regard, the angle of the needlecan be adjusted until the patient exhibits a desired response with theconducting of electricity through the needle.

For some clinical situations, the first distance is 2 cm, the seconddistance is 4 cm, and the third distance is 5 cm.

Another aspect of the disclosure relates to a method for positioning aforamen needle to implant a lead of an electrical stimulator for sacralneuromodulation of a patient. The disclosed method comprises:

-   -   1. visualizing with fluoroscopy an anterior/posterior view of        the sacrum and sacroiliac joints of the patient;    -   2. marking on the skin of the patient a midline of the sacrum        vertically and a horizontal line from one sacroiliac joint to        the other sacroiliac joint;    -   3. marking a first point on the horizontal line 2 cm in a first        lateral direction from the sacral midline and a second point on        the horizontal line 2 cm in a second lateral direction from the        sacral midline;    -   4. locating a first midline of a desired sacral foramen using        the fluoroscopic anterior/posterior view and the first point and        marking the skin of the patient with a first midline vertical        line;    -   5. locating a second midline of another desired sacral foramen        using the fluoroscopic anterior/posterior view and the second        point and marking the skin of the patient with a second midline        vertical line, the another desired sacral foramen opposite the        desired sacral foramen;    -   6. marking the skin of the patient at 4 cm and 5 cm from the        horizontal line superiorly on the first midline vertical line,        thereby approximating where the desired foramen should be        located to place the needle;    -   7. marking the skin of the patient at 4 cm and 5 cm from the        horizontal line superiorly on the second midline vertical line,        thereby approximating where the another desired foramen should        be located to place the needle;    -   8. marking the skin of the patient with a first medial vertical        line representing the medial portion of the first sacral edge        using the fluoroscopic anterior/posterior view;    -   9. marking the skin of the patient with a second medial vertical        line representing the medial portion of the second sacral edge        using the fluoroscopic anterior/posterior view;    -   10. locating the desired sacral foramen with fluoroscopy in a        lateral view; and    -   11. placing the needle through the skin at an angle using the        skin markings at one of the 4 cm and 5 cm markings, beginning        medially at the first midline vertical line and progressing        laterally to the first medial vertical line until a distal end        of the needle drops into the desired sacral foramen.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present disclosure, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic illustration showing a conventional sacral nervestimulator system.

FIG. 2 is a schematic illustration showing needle positioning.

FIG. 3 is an anterior-posterior fluoroscopic image of the sacrum showinglines and markings made according to the disclosed method.

FIG. 4 is a lateral fluoroscopic image of the sacrum showing lines andmarkings made according to the disclosed method.

FIG. 5 is a lateral fluoroscopic image of the sacrum showing optimalplacement of the needle.

FIG. 6 is an anterior-posterior fluoroscopic image of the sacrum showingoptimal placement of the needle.

FIG. 7 is an anterior-posterior fluoroscopic image of the sacrum showinglead positioning achieved using the disclosed method.

FIG. 8 is a lateral fluoroscopic image of the sacrum showing leadpositioning achieved using the disclosed method.

FIG. 9 is a photograph showing skin markings made according to thedisclosed method.

DETAILED DESCRIPTION

As required, embodiments are disclosed herein; however, it is to beunderstood that the disclosed embodiments are merely examples and thatthe methods described below can be embodied in various forms. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a representative basis forteaching one skilled in the art to variously employ the present subjectmatter in virtually any appropriately detailed structure and function.Further, the terms and phrases used herein are not intended to belimiting, but rather, to provide an understandable description of theconcepts.

The terms “a” or “an”, as used herein, are defined as one or more thanone. The term plurality, as used herein, is defined as two or more thantwo. The term another, as used herein, is defined as at least a secondor more. The terms “including” and “having,” as used herein, are definedas comprising (i.e., open language). The term “coupled,” as used herein,is defined as “connected,” although not necessarily directly, and notnecessarily mechanically.

FIG. 1 shows a conventional sacral nerve stimulator system 10. System 10includes an implant (stimulator) 12 which is implanted proximal thepatient's iliac crest 14 and a wire lead (having one or more electrodes)16 which extends from implant 12 to the sacral nerves 18 that emergefrom the spine 20 to control, among other things, urinary function ofthe bladder 22 and urethra 24. The electrodes at the distal end of thewire lead 16 are positioned proximal the sacral nerves 18 using aforamen needle 26. FIG. 2 shows needle 26 inserted through a foramen 28.After the distal end of the wire lead 16 is positioned, a tunneller isinserted through the puncture wound created by foramen needle 26 tosubcutaneously extend wire lead 16 to stimulator 12. Thus, stimulator 12and wire lead 16 are completely implanted. An external control 30 isused to program or control the delivery of electrical pulses to sacralnerves 18 from implant 12 through wire lead 16.

With reference to FIGS. 1-9, an embodiment of the disclosed methods forneedle positioning and lead implantation for sacral neuromodulation isnow described.

As is well known, the patient is positioned prone on the procedure tablewith bolsters to make the patient's sacrum flat on the table. Thepatient is prepped and draped in a conventional manner

Under fluoroscopy in the Anterior/Posterior view, the practitioner marksthe midline of the sacrum vertically 32 and the sacroiliac jointshorizontally 34 on the patient's skin. FIG. 3 shows lines 32, 34 on thefluoroscopic image on the computer monitor and FIG. 9 shows lines 32, 34made on the skin of the patient. Any suitable marker or similarimplement can be used to make the lines and/or marks. If desired, astraight edge can be used in making the lines and/or marks.

Following horizontal line 34, the practitioner measures and marks 2 cmon the skin from vertical line 32 to give an approximation of where tobegin to find the foraminal midline. As one of ordinary skill in the artwill appreciate, 2 cm is chosen since this distance is an approximationfor the human sacrum (based on standard anatomical sizes) to provide astarting point for where to begin finding the foraminal midline of S2,S3, or S4. The disclosure contemplates that the practitioner can deviatefrom 2 cm (for example, if the patient is of small or large stature).The disclosure also contemplates that a distance other than 2 cm can beused for other clinical situations (e.g. lumbar neuromodulation).

It should be noted that any skin markings as disclosed herein do notnecessarily correlate to the exact distance appearing on fluoroscopy asthere is space between the skin and actual sacrum secondary to tissue.The concept is to measure on the skin for an approximation of where tofind the sacral #3 foramen fluoroscopically. The needle is passedthrough sacral #3 foramen for lead placement. The sacral #3 foramen isselected as it generally provides access to the sacral spinal nerve #3,which is targeted for bladder and bowel control. In some individuals,other sacral foramen (e.g. sacral #2 foramen or sacral #4 foramen)provide better access to the sacral spinal nerve #3. In other cases aspreviously noted, a different nerve may be selected for neuromodulation.Accordingly, the present disclosure contemplates access through otherforamen and neuromodulations of other nerves.

Using fluoroscopy in the Anterior/Posterior view and the 2 cm markings,the practitioner finds the midline of the sacral foramen #3 bilaterallyand draws a vertical line 36 at the midline of sacral foramen #3bilaterally on the skin. Although the figures and this detaileddescription show and describe bilaterally location, the disclosurecontemplates unilateral location, i.e. marking on one side of the spine.Subject to anatomical variation vertical line 36 is parallel to verticalline 32.

The practitioner makes a skin marking at 4 cm (marking 38) and 5 cm(marking 40) from horizontal line 34 superiorly bilaterally on verticalline 36 to give an approximation of where the foramen should be locatedto place the needle. The disclosure contemplates that the practitionercan deviate from 4 cm and/or 5 cm (for example, if the patient is ofsmall or large stature). The disclosure also contemplates that distancesother than 4 cm and/or 5 cm can be used for other clinical situations(e.g. lumbar neuromodulation).

Using fluoroscopy in the Anterior/Posterior view, the practitionervertically marks the medial portion of the sacral edge bilaterally (line42).

Line 42 indicates the absolute medial aspect of the sacrum for which theneedle can be placed and line 36 indicates the near-absolute lateralaspect for which the Sacral #3 nerve will be located. This provides ananterior/posterior guideline for needle placement while changing needleangle placement in the lateral view.

As shown in FIG. 4, in the lateral fluoroscopic view, the practitionerfinds the sacral #3 foramen visually. The practitioner then beginsplacing needle through the skin at an approximately 45-degree angleusing the skin markings in the anterior view at the 4 cm (marking 38) or5 cm (marking 40) markings beginning medially (using line 42 as alandmark) and progressing to the most lateral edge (using line 36 as alandmark) until the needle drops into the sacral #3 foramen. The needleangle insertion may be varied depending on the patient's body habitus.The practitioner confirms this placement in the lateral fluoroscopicview and adjusts the angle with minute movements of the needle until theneedle is 1 cm from the inferior edge of sacral foramen #3 and parallelto the inferior edge of sacral foramen #3. Needle 26 is schematicallyshown in this position in FIG. 5.

The practitioner confirms placement of needle 26 in theAnterior/Posterior view for medial placement of needle 26, i.e.approximately parallel to vertical line 42. The practitioner can adjustneedle 26 in the Anterior/Posterior and Lateral views until optimalneedle placement is achieved in each view. This is shown in FIGS. 5 and6.

As is known, the practitioner can test needle 26 for optimal placementresulting in the patient experiencing anal bellows and toe flexion at 2mA or less of stimulation. The practitioner can continue to adjust theneedle in the Anterior/Posterior and Lateral views using minutemovements and angle changes until the desired result is achieved.

Once this is achieved, the practitioner places the lead into the Sacral#3 foramen according to standard procedure. The practitioner can conductanother test with the lead to ensure the patient experiences analbellows and toe flexion on all electrodes at 2 mA or less ofstimulation. If this is not achieved, the practitioner can remove thelead and begin with needle placement again until the desired response isachieved with the lead.

FIGS. 7 and 8 show lead 16 with four electrodes 44 positioned accordingto the disclosed method.

All references cited herein are expressly incorporated by reference intheir entirety. It will be appreciated by persons skilled in the artthat the present disclosure is not limited to what has been particularlyshown and described herein above. In addition, unless mention was madeabove to the contrary, it should be noted that all of the accompanyingdrawings are not to scale. There are many different features to thepresent disclosure and it is contemplated that these features may beused together or separately. Thus, the disclosure should not be limitedto any particular combination of features or to a particular applicationof the disclosure. Further, it should be understood that variations andmodifications within the spirit and scope of the disclosure might occurto those skilled in the art to which the disclosure pertains.Accordingly, all expedient modifications readily attainable by oneversed in the art from the disclosure set forth herein that are withinthe scope and spirit of the present disclosure are to be included asfurther embodiments of the present disclosure.

What is claimed is:
 1. A method for positioning a foramen needle toimplant a lead of an electrical stimulator for sacral neuromodulation ofa patient, the method comprising: visualizing with fluoroscopy ananterior/posterior view of the sacrum and sacroiliac joints of thepatient; marking on the skin of the patient a midline of the sacrumvertically and a horizontal line from one sacroiliac joint to the othersacroiliac joint; marking a first point on the horizontal line located afirst distance in a first lateral direction from the sacral midline,wherein the first distance approximates a first midline of a desiredsacral foramen; locating the first midline of the desired sacral foramenusing the fluoroscopic anterior/posterior view and the first point andmarking the skin of the patient with a first midline vertical line;marking the skin of the patient at a second distance and a thirddistance from the horizontal line superiorly on the first midlinevertical line, thereby approximating where the desired foramen should belocated to place the needle; marking the skin of the patient with afirst medial vertical line representing the medial portion of the firstsacral edge using the fluoroscopic anterior/posterior view; locating thedesired sacral foramen with fluoroscopy in a lateral view; placing theneedle through the skin at an angle using the skin markings at one ofthe second and third markings, beginning medially at the first midlinevertical line and progressing laterally to the first medial verticalline until a distal end of the needle drops into the desired sacralforamen.
 2. The method of claim 1, further comprising: marking a secondpoint on the horizontal line located the first distance in a secondlateral direction from the sacral midline; locating a second midline ofanother desired sacral foramen using the fluoroscopic anterior/posteriorview and the second point and marking the skin of the patient with asecond midline vertical line, the another desired sacral foramenopposite the desired sacral foramen; marking the skin of the patient atthe second distance and the third distance from the horizontal linesuperiorly on the second midline vertical line, thereby approximatingwhere the another desired foramen should be located to place the needle;and marking the skin of the patient with a second medial vertical linerepresenting the medial portion of the second sacral edge using thefluoroscopic anterior/posterior view.
 3. The method of claim 2, whereinthe needle angle is approximately 45 degrees.
 4. The method of claim 2,wherein the needle angle depends on the body habitus of the patient. 5.The method of claim 2, wherein the placing of the needle is done underfluoroscopic visualization.
 6. The method of claim 5, wherein after thedistal end of the needle drops into the desired sacral foramen, theangle of the needle is adjusted until the needle is 1 cm from theinferior edge of the desired sacral foramen and parallel to the inferioredge of the desired sacral foramen.
 7. The method of claim 6, furthercomprising adjusting the angle of the needle using the fluoroscopicanterior/posterior view until the needle is parallel to the first medialvertical line.
 8. The method of claim 7, further comprising conductingelectricity through the needle to confirm placement of the needle. 9.The method of claim 8, further comprising adjusting the angle of theneedle until the patient exhibits a desired response with the conductingof electricity through the needle.
 10. The method of claim 1, whereinthe first distance is 2 cm, the second distance is 4 cm, and the thirddistance is 5 cm.
 11. A method for positioning a foramen needle toimplant a lead of an electrical stimulator for sacral neuromodulation ofa patient, the method comprising: visualizing with fluoroscopy ananterior/posterior view of the sacrum and sacroiliac joints of thepatient; marking on the skin of the patient a midline of the sacrumvertically and a horizontal line from one sacroiliac joint to the othersacroiliac joint; marking a first point on the horizontal line 2 cm in afirst lateral direction from the sacral midline and a second point onthe horizontal line 2 cm in a second lateral direction from the sacralmidline; locating a first midline of a desired sacral foramen using thefluoroscopic anterior/posterior view and the first point and marking theskin of the patient with a first midline vertical line; locating asecond midline of another desired sacral foramen using the fluoroscopicanterior/posterior view and the second point and marking the skin of thepatient with a second midline vertical line, the another desired sacralforamen opposite the desired sacral foramen; marking the skin of thepatient at 4 cm and 5 cm from the horizontal line superiorly on thefirst midline vertical line, thereby approximating where the desiredforamen should be located to place the needle; marking the skin of thepatient at 4 cm and 5 cm from the horizontal line superiorly on thesecond midline vertical line, thereby approximating where the anotherdesired foramen should be located to place the needle; marking the skinof the patient with a first medial vertical line representing the medialportion of the first sacral edge using the fluoroscopicanterior/posterior view; marking the skin of the patient with a secondmedial vertical line representing the medial portion of the secondsacral edge using the fluoroscopic anterior/posterior view; locating thedesired sacral foramen with fluoroscopy in a lateral view; placing theneedle through the skin at an angle using the skin markings at one ofthe 4 cm and 5 cm markings, beginning medially at the first midlinevertical line and progressing laterally to the first medial verticalline until a distal end of the needle drops into the desired sacralforamen.
 12. The method of claim 11, wherein the needle angle isapproximately 45 degrees.
 13. The method of claim 11, wherein the needleangle depends on the body habitus of the patient.
 14. The method ofclaim 11, wherein the placing of the needle is done under fluoroscopicvisualization.
 15. The method of claim 14, wherein after the distal endof the needle drops into the desired sacral foramen, the angle of theneedle is adjusted until the needle is 1 cm from the inferior edge ofthe desired sacral foramen and parallel to the inferior edge of thedesired sacral foramen.
 16. The method of claim 15, further comprisingadjusting the angle of the needle using the fluoroscopicanterior/posterior view until the needle is parallel to the first medialvertical line.
 17. The method of claim 16, further comprising conductingelectricity through the needle to confirm placement of the needle. 18.The method of claim 17, further comprising adjusting the angle of theneedle until the patient exhibits a desired response with the conductingof electricity through the needle.